The present invention relates to pyridazinone derivatives of general formula I
wherein the groups A, G and R1 are defined as hereinafter, including the tautomers thereof, stereoisomers (e.g. diastereomers and enantiomers), the mixtures thereof and the salts thereof, particularly the pharmaceutically acceptable salts thereof, which have valuable pharmacological properties, in particular they bind to the G-protein-coupled receptor GPR119 (also known as GPCR2, RUP3, SNORF25 or GDIR) and modulate its activity.
These compounds according to the invention may be used in the pharmaceutical industry for preparing pharmaceutical compositions for human and/or veterinary medicine.
The invention further relates to pharmaceutical compositions containing one or more compounds according to the invention as well as the use of the compounds according to the invention as medicaments, particularly for preparing pharmaceutical compositions for the therapeutic treatment of metabolic disorders, particularly obesity and diabetes, especially type 2 diabetes, and the complications thereof and/or associated diseases. In addition, the invention relates to processes for preparing the compounds and pharmaceutical compositions according to the invention.
Diabetes mellitus is a serious metabolic disease which affects more than 100 million people worldwide. In the USA there are more than 12 million diabetics with 600,000 new cases diagnosed every year. The prevalence of diabetes mellitus is on the increase, which means in particular a high frequency of complications as well, leading to a substantial impairment of quality of life and life expectancy. Because of diabetes-associated microvascular complications, in the industrialised countries type 2 diabetes is currently the most common cause of adult-onset loss of vision, renal insufficiency and amputations. In addition, type 2 diabetes is associated with a two- to five-fold increase in the risk of cardiovascular disease.
The UKPDS study (United Kingdom Prospective Diabetes Study) showed that intensive treatment with common therapeutic agents, e.g. metformin, sulphonylureas or insulin, results in only a limited improvement in glycaemic control (difference in the HbA1c value ˜0.9%). Moreover, glycaemic control deteriorated considerably over time even in patients in the intensive treatment group, and this was put down to a deterioration in beta cell function. Diabetes is also a major cause of damage to the retina at the back of the eye and increases the risk of cataract and glaucoma. Finally, diabetes is associated with nerve damage, particularly in the legs and feet, which affects the patient's ability to feel pain and contributes to serious infections. All in all, complications of diabetes are one of the major causes of death worldwide.
Adiposity (obesity) is the result of an imbalance between calorie intake and energy consumption. It correlates to a high degree with insulin resistance and diabetes. However, the molecular mechanisms that are involved in obesity/diabetes syndromes are not yet clear. At an early stage of the development of obesity, an increased insulin secretion balances out the insulin resistance and protects the patient from hyperglycaemia. However, after a time, the beta cell function worsens and non-insulin-dependent diabetes develops in about 20% of the obese population. Obesity has thus become a critical risk factor for diabetes, but the factors that predispose one group of patients to a pathological change in insulin secretion as a response to the accumulation of fat are currently unknown.
Obesity also significantly increases the risk of the development of cardiovascular disease. Diabetes is also implicated in the formation of kidney complaints, eye complaints and problems of the nervous system. Kidney disease, also known as nephropathy, sets in when the filtering mechanism of the kidneys is disrupted and proteins escape into the urine in excessive amounts and finally the kidney fails. Therefore there is a medical need for medicaments for preventing and/or treating metabolic disorders (particularly diabetes, predominantly type 2 diabetes) and the complications thereof. In particular there is a need for medicaments with good activity in terms of glycaemic control, disease-modifying properties and reducing cardiovascular morbidity and mortality, and which also have a better safety profile.
GPR119 is a Gs-protein coupled receptor which is expressed overwhelmingly in the beta cells of the pancreas and in the L cells of the bowel. Activation of the receptor stimulates the cAMP signal pathway, in the way that GLP-1R agonists do. Therefore, a GPR119 agonist can be expected to bring about an improvement in the beta cell function and the beta cell mass. In fact, activation of GPR119 stimulates insulin secretion in-vitro and in-vivo (in rodents) in a glucose-dependent manner. It has recently been shown that GPR agonists effectively lower the blood glucose level in diabetic rodents without the risk of hypoglycaemia. In addition, GPR119 expression has been observed in the gastrointestinal tract and in the brain of rodents, but not in the human brain. It was shown that the activation of GPR119 in neuroendocrine cells of the bowel stimulates the release of GLP-1, therefore the activation of GPR119 combines a direct effect on the beta cells with an indirect glucoregulatory effect through an intestinal increase in the release of GLP-1. Therefore the GPR119 agonists may be expected to have a therapeutic benefit in metabolic diseases. Examples of such diseases include type 1 diabetes, type 2 diabetes, insufficient glucose tolerance, insulin resistance, hyperglycaemia, hyperlipidaemia, hypercholesterolaemia, dyslipidaemia, syndrome X, metabolic syndrome, obesity, high blood pressure, chronic systemic inflammation, retinopathy, neuropathy, nephropathy, atherosclerosis, endothelial dysfunction and bone-related diseases (such as osteoporosis, rheumatoid arthritis or osteoarthritis).
The publication EP 0196005 describes certain pyridazinone derivatives and their medical use based on a cardiotonic and/or hypotensive and antithrombotic activity.